1. Field of the Invention
The present invention relates to a semiconductor chip and a thin-type semiconductor device using the same.
2. Description of Related Art
To produce a thinner semiconductor device, studies have recently been made on a package having a thickness substantially equal to that of a semiconductor chip (chip thickness package)
FIG. 5 is a side view schematically illustrating a conventionally proposed arrangement to achieve a chip thickness package. In this conventionally proposed arrangement, film-like electrodes 93 are connected to the undersides of lead frames 91 through bumps 92. A semiconductor chip 95 having bumps 94 on its face at the active-surface-layer-area side, is connected to the film-like electrodes 93 through the bumps 94 with the face at the active-surface-layer-area side being opposite to the tops of the film-like electrodes 93. The connection part between each lead frame 91 and each film-like electrode 93 and the connection part between each film-like electrode 93 and the semiconductor chip 95, are sealed as wholly covered with resin 96 to prevent separation from each other.
According to the arrangement above-mentioned, however, each of the film-like electrodes 93 and the bumps 92, 94 has a thickness of about 20xcx9c30 xcexcm. This accordingly increases the semiconductor device in thickness. It is therefore impossible to achieve a chip thickness package having a thickness substantially equal to that of the semiconductor chip 95.
It is an object of the present invention to provide a semiconductor chip which makes it possible to achieve a chip thickness package, and also to provide a semiconductor device formed with the use of such a semiconductor chip.
According to the present invention, a semiconductor chip is provided at a lateral face thereof with an electrode for external electric connection.
When the semiconductor chip has a plurality of electrodes, each of these electrodes preferably formed at a lateral face of the semiconductor chip.
The lateral face refers to an outer face extending along the thickness direction of the semiconductor chip.
According to the present invention, each electrode is formed at a lateral face of a semiconductor chip. Accordingly, a power supply or signal wire (bonding wire) to be connected to each electrode can be connected laterally of the semiconductor chip. This eliminates the need to dispose, on a surface of the semiconductor chip, a bump or the like for external electric connection. Therefore, a semiconductor device formed with the use of this semiconductor chip is made in the form of a chip thickness package having a thickness substantially equal to that of the semiconductor chip.
Each electrode is preferably embedded in a groove which is formed in a lateral face of the semiconductor chip and which is opened laterally of the semiconductor chip. This arrangement can reduce the semiconductor chip in size in plan view, thus achieving further miniaturization of the semiconductor device.
When the semiconductor chip is a discrete device comprising a bipolar transistor, the collector electrode is preferably formed at a lateral face of the semiconductor chip. Further, all the base electrode, the emitter electrode and the collector electrode are preferably formed at one or more lateral faces of the semiconductor chip. More preferably, all the electrodes are formed at (preferably, exposed to) the side of the same surface (outer surface at a right angle to the thickness direction of the semiconductor chip) of the semiconductor chip.
The collector electrode of a conventional bipolar transistor is formed in a collector area formed at the underside of the semiconductor chip. Accordingly, a collector frame is present at the underside of the semiconductor chip. This prevents the thickness of the semiconductor device from being made substantially equal to that of the semiconductor chip. On the contrary, when the collector electrode is formed at a lateral face of the semiconductor chip, the collector frame can be connected to the collector electrode laterally of the semiconductor chip, thus eliminating the need to extend the collector frame to the underside of the semiconductor chip. This achieves a chip thickness package having a thickness substantially equal to that of the semiconductor chip.
According to the present invention, a semiconductor device comprises a semiconductor chip having the characteristics above-mentioned, and a power supply or signal wire connected, laterally of the semiconductor chip, to each electrode.